A5032227675- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Radio Astronomy Observations and Technology
- Astrophysical Phenomena and Observations
- High-pressure geophysics and materials
- GNSS positioning and interference
- Stellar, planetary, and galactic studies
- Magnetic confinement fusion research
- Inertial Sensor and Navigation
- Geophysics and Sensor Technology
- Nuclear Physics and Applications
- Welding Techniques and Residual Stresses
- Particle accelerators and beam dynamics
- High-Energy Particle Collisions Research
- Astro and Planetary Science
- Molecular spectroscopy and chirality
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Industrial Vision Systems and Defect Detection
- Non-Destructive Testing Techniques
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Seismic Waves and Analysis
Guizhou Normal University
2014-2024
National Astronomical Observatories
2017-2024
Chinese Academy of Sciences
2017-2024
Nanjing University of Science and Technology
2018-2022
Nanjing Institute of Astronomical Optics & Technology
2022
China Academy of Space Technology
2018
University of Chinese Academy of Sciences
2017
Abstract The minimum variation timescale (MVT) of soft gamma-ray repeaters can be an important probe to estimate the emission region in pulsar-like models, as well Lorentz factor and radius possible relativistic jet burst (GRB)–like thus revealing their progenitors physical mechanisms. In this work, we systematically study MVTs hundreds X-ray bursts (XRBs) from SGR J1935+2154 observed by Insight-HXMT, GECAM, Fermi/Gamma-ray Burst Monitor 2014 July 2022 January through Bayesian block...
Abstract We report on radio observations of four magnetars SGR 0501+4516, Swift 1834.9–0846, 1E 1841–045, 1900+14, and a magnetar-like pulsar PSR J1846–0258 with the Five-hundred-meter Aperture Spherical Telescope at 1250 MHz. Notably, was observed 1 month after its 2020 X-ray outburst. The data from these were searched for periodic emissions single pulses. No emission detected any our targets. After accounting effect red noise, nondetections yield stringent upper limits flux density, S ≤...
Abstract Whether the X-ray emissions of strong jet sources originate from disk+coronas or jets is still controversial. In this work, we constructed a sample containing 50 flat-spectrum radio quasars, 51 low-synchrotron-peaked BL Lac objects, and 18 intermediate-synchrotron-peaked objects to explore origin emissions. Generally, blazars are typical radio-loud active galactic nucleus with powerful toward observer, causing their broadband be boosted. By considering Doppler boosting effect,...
We utilized archived data from the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) to analyze single-pulse profile morphology of PSR J1935$+$1616 (B1933$+$16). The results show that exhibits significant micropulses as well various changes in morphology. In FAST data, a total 969 single pulses with microstructure were identified, accounting for 9.69$\%$ pulse sample, characteristic widths $127.63^{+70.74}_{-46.25}$ $\mu$s. About half these display quasiperiodic micropulses,...
Abstract We utilized archive data from the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) to analyze single-pulse profile morphology of PSR J1935+1616 (B1933+16). The results show that exhibits significant micropulses as well various changes in morphology. In FAST data, a total 969 single pulses with microstructure were identified, accounting for 9.69% pulse sample, characteristic widths <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">...
ABSTRACT Spectral lag of the low-energy photons with respect to high-energy ones is a common astrophysical phenomenon (such as gamma-ray bursts and Crab Pulsar) may serve key probe underlying radiation mechanism. However, spectral in keV range magnetar has not been systematically studied yet. In this work, we perform detailed analysis Li et al.’s Cross-Correlation Function (Li-CCF) method for SGR J1935+2154 observed by Insight-Hard X-ray Modulation Telescope (HXMT), Gravitational Wave...
Abstract The study of polarization and micro-structure is very important for understanding the radiation mechanism Rotating Radio Transients (RRATs). Due to limitations telescope sensitivity time resolution, studies RRATs have been rare in past. In this work, we report on a high-time resolution full observation RRAT J0139+3336 with Five-hundred-meter Aperture Spherical Telescope (FAST). A total 96 burst pulses were detected 3-hour observation. degrees linear circular shape position angle...
ABSTRACT PSR B0820 + 02 is known to exhibit the subpulse drifting phenomenon, which carries vital information about pulsar radiation process. In this work, we studied of at a central frequency 1250 MHz using Five-hundred-meter Aperture Spherical radio Telescope (FAST). Thanks superior sensitivity FAST, found that shows four distinct modes (A, B, C, and D), last three have not been reported before. The periodicities these are be 4.3P1, 6.4P1, 8.2P1, 10.3P1 (P1 pulse period), respectively. No...
Abstract We observed the nearby radio pulsar B0950+08, which has a 100% duty cycle, using Five-hundred-meter Aperture Spherical Radio Telescope. obtained polarization profile for its entire rotation, enabled us to investigate magnetospheric radiation geometry and sparking pattern of polar cap. After we excluded part in linear factor is low (≲30%) potentially contaminated by jumps position angle, rest swing angle fits classical rotating vector model (RVM) well. The best-fit RVM indicates that...
Abstract This study presents a comprehensive analysis of the spectral properties 886 pulsars across wide frequency range from 20 MHz–343.5 GHz, including total 86 millisecond (MSPs). The majority exhibit power-law behavior in their spectra, although some exceptions are observed. Five different models, namely, simple power law, broken low-frequency turnover, high-frequency cutoff, and double were employed to explore behaviors. average index for modeled with law is found be −1.64 ± 0.80,...
ABSTRACT The multidrifting subpulse behaviours in PSR J2007 + 0910 have been studied carefully with the high sensitivity observations of Five-hundred-meter Aperture Spherical radio Telescope (FAST) at 1250 MHz. We found that there are least six different single emission modes observed, four which show significant drifting (modes A, B, C, and D), remaining two E1 E2) stationary structures. periods D P3,A = 8.7 ± 1.6P, P3,B 15.8 1.2P, P3,C 21.6 1.3P, P3,D 32.3 0.9P, respectively, where P...
The emission geometries, e.g. the region height, beam shape, and radiusto-frequency mapping, are important predictions of pulsar radiation model.The multiband radio observations carry such valuable information.In this paper, we study two bright pulsars, (PSRs B0329+54 B1642-03) observe them in high frequency (2.5 GHz, 5 8 GHz).The newly acquired data together with historical archive provide an atlas multi-frequency profiles spanning from 100 MHz to 10 GHz.We evolution pulse regions these...
We present the first measurement of pulse scattering close to eclipse region PSR B1957+20, which is in a compact binary system with low-mass star. measured time-scales up 0.2 ms and showed that it scales dispersion measure (DM) excess roughly as $\tau\propto\Delta{\rm DM}^{2}$. Our observations provide evidence strong due multi-path propagation effects eclipsing material. show Kolmogorov turbulence material an inner scale $\sim100$ m outer size can naturally explain observation. results such...
Abstract In the eighth data release (DR8) of Large Sky Area Multi-Object Fiber Spectroscopic Telescope, more than 318,740 low-resolution stellar spectra with types from B to early F and signal-to-noise ratios >50 were released. With this large volume early-type stars, we tried machine-learning algorithms search for class-one class-two chemical peculiars (CP1 CP2), detect spectral features distinguish two classes in spectra. We selected XGBoost algorithm after comparing classification...
Aiming at the problems of scarce datasets and low identification accuracy faced in field weld-crack detection, this paper proposes an artificial-weld-crack preparation method based on doping dissimilar metal particles to augment number samples defects. Meanwhile, data augmentation methods such as random cropping, scaling Mosaic are combined further enhance richness samples, so provide strong support for proposed weld-crack-defect detection model. Given limitations storage computational...
Integrated pulse profiles at 8.6~GHz obtained with the Shanghai Tian Ma Radio Telescope (TMRT) are presented for a sample of 26 pulsars. Mean flux densities and width parameters these pulsars estimated. For eleven first high-frequency observations further four, our have better signal-to-noise ratio than previous observations. one (PSR J0742-2822) differs from previously observed profiles. A comparison 19 those other frequencies shows that in nine cases separation between outmost leading...
ABSTRACT The pulse profile of PSR B1133+16 is usually regarded as a conal double structure. However, its multi-frequency profiles cannot simply be fitted with two Gaussian functions, and third component always needed to fit the bridge region (between peaks). This would introduce additional, redundant parameters. In this paper, through comparison five fitting functions (Gaussian, von Mises, hyperbolic secant, square Lorentz), it found that secant function can best reproduce profile, yielding...
Abstract We report the observations of periodic nulling in PSR B2111+46 at 1250 MHz with Five-hundred-meter Aperture Spherical radio Telescope (FAST). The fractions (NF) as well period this pulsar were calculated. NF and are 17% ± 1% 62.49 0.99 P 1 , respectively, shows variations periodicity time. durations each consecutive burst investigated, which show that power-law distribution indices −1.11 0.04 −2.08 0.23. In observed frequency band, width profile is narrowed increase frequency,...
Abstract The frequency evolution behavior of radio pulse profiles is an important clue for the radiation mechanism a pulsar. Combined with latest results European Pulsar Network and Australia Telescope National Facility data, we systematically study W 50 (the full width profile at 50% pulsar amplitude) 74 pulsars frequencies from tens to thousands megahertz. We find that 71 show “absorption” features, which indicates absorption universal phenomenon in population independent type profile. It...
Abstract We report a detailed study of polarization characteristics and subpulse drifting in PSR J1110−5637 with the observations Parkes 64 m radio telescope at 1369 MHz. The revealed that trailing component pulse profile has obvious drifting, while leading no drifting. Using two-dimensional fluctuation spectrum (2DFS), we detected three distinct emission modes (modes A, B C). mode A is chaotic indistinguishable, C have vertical modulation periods P 3 are around mean values 12 8 P,...
Abstract The radio radiation mechanism is one of the open questions for pulsars. Multiband observations are very helpful to constrain pulsar models. We observed PSR J1848-0123 at 5 GHz band with Shanghai Tianma 65 m telescope (TMRT). observation together European Pulsar Network (EPN) and CSIRO ATNF Data Archives databases provides a broadband evolution property pulse profiles this pulsar. reprocessed these data sets obtain multiband profiles. It was found that profile narrows increasing...
Abstract We report the “Bi-drifting” subpulses observed in PSR J0815+0939 using Five-hundred-meter Aperture Spherical radio Telescope (FAST). The observation at band from 1050 to 1450 MHz is evenly divided into two bands, i.e., bands center frequencies of 1150 and 1350 MHz. mean pulse profiles these are investigated. It found that show four emission components, peak separations between components decrease with increase frequency. In addition, ratio intensity each component IV larger than...
The determination of the absolute and relative position a spacecraft is critical for its operation, observations, data analysis, scientific studies, as well deep space exploration in general. A that can determine own autonomously may perform more than must rely on transmission solutions. In this work, we report an navigation accuracy $\sim$ 20 km using 16-day Crab pulsar observed with $Fermi$ Gamma ray Burst Monitor (GBM). addition, propose new method inverse process triangulation joint...